// Copyright 2009 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include <stddef.h>

#include "runtime_types.h"
#include "type.h"
#include "string.h"

// The 64-bit type.

typedef unsigned int DItype __attribute__ ((mode(DI)));

// An identity hash function for a type.  This is used for types where
// we can simply use the type value itself as a hash code.  This is
// true of, e.g., integers and pointers.

uintptr
__go_type_hash_identity(const void *key, uintptr key_size)
{
	uintptr ret;
	uintptr i;
	const unsigned char *p;

	if (key_size <= 8) {
		union {
			DItype v;
			unsigned char a[8];
		} u;
		u.v = 0;
#ifdef WORDS_BIGENDIAN
		__builtin_memcpy(&u.a[8 - key_size], key, key_size);
#else
		__builtin_memcpy(&u.a[0], key, key_size);
#endif
		if (sizeof(uintptr) >= 8)
			return (uintptr) u.v;
		else
			return (uintptr) ((u.v >> 32) ^ (u.v & 0xffffffff));
	}

	ret = 5381;
	for (i = 0, p = (const unsigned char *)key; i < key_size; i++, p++)
		ret = ret * 33 + *p;
	return ret;
}

// An identity equality function for a type.  This is used for types
// where we can check for equality by checking that the values have
// the same bits.

_Bool
__go_type_equal_identity(const void *k1, const void *k2, uintptr key_size)
{
	return __builtin_memcmp(k1, k2, key_size) == 0;
}
